1. Field of the Invention
The present invention relates to a flash fixation apparatus for fixing toners on a medium by means of flash light and a printer using the same, and more particularly a flash fixation apparatus for collecting gas produced from the toners during flash fixation and a printer using the same.
2. Description of the Related Art
In a printer for forming toner images in which the electrophotographic scheme of the like is employed, an image is formed by means of a powder toner on a print medium. The toner image is then fixed by fusing the powder toner placed on the print medium. To fix the toner image, it is necessary to apply fixation energy onto the print medium.
In a high-speed printer, a non-contact type fixation method is employed as a fixation method for applying the fixation energy. It is suitable to use the non-contact type fixation method in the high-speed printer because high fixation energy can be applied without influencing transportation of the print medium.
As one method of this non-contact type fixation method, a flash fixation method employing flash light produced by a flash lamp. In the flash fixation method, light is emitted from the flash lamp at predetermined intervals corresponding to the transportation of the print medium to fix on each predetermined area of the print medium.
FIG. 18 shows a configuration diagram of the conventional flash fixation unit. In a flash fixation unit 13, a flash lamp 101 and a reflection plate 102 are accommodated in a lamp house 100. The lamp house 100 on the paper 110 side is covered with a glass plate 103 to isolate the internal portion of the lamp house 100 from outside.
A toner image 114 is formed on the paper 110 guided by a pair of carrying rollers 112 and 116. The paper 110 is carried continuously while maintaining a position opposite to the glass plate 103 and is received the flashlight emitted from the flash lamp 101. The toner 114 on the paper 110 is abruptly heated by the energy applied from the flashlight, producing gas (evaporated gas) C from the toner 114.
Gas C adheres onto the flash lamp 101, the glass plate 103 for protecting the lamp 101, the print paper 110, the carrying roller 116 outside the fixation unit, etc. If the gas having adhered is not removed, the gas may cause a failure, such as a decreased fixation ratio, degraded print quality and malfunction of medium transportation.
Conventionally, in order to circumvent this problem, there has been provided a suction mechanism (or degassing mechanism) 104 on the rear side of the flash fixation unit for collecting the gas (evaporated gas) C to suck and deodorize. This mechanism enables to prevent gas adhesion to the lamp house 100, the paper 110 and the carrying roller 116, by which smell diffusion can also be prevented.
However, as print speed of a printer becomes higher in recent years, transportation speed of the paper 110 becomes higher and, at the same time, higher fixation speed is required. This has required an increased amount of gas generation produced from the toner 114 on the paper 110, resulting in a tendency of gas leakage in the downstream side of the flash fixation unit, that is the transportation direction of the paper 110, as shown by arrow B.
To prevent the gas leakage in the conventional art, it is normally necessary to increase either suction power or suction area so that the produced gas can be sufficiently sucked by suction mechanism 104, as shown in FIG. 19, and gas collection efficiency can be increased.
However, when increasing the suction power, pressure to float up out of the transportation plane is produced on the paper 110, caused by the gas (evaporated gas) suction with an increased wind velocity/pressure. This produces the paper under transportation to flutter easily.
In the conventional configuration, the paper 110 is guided by the carrying rollers 112 and 116 disposed at the front and rear sides of the flash fixation unit, which produces a reduced tension of the paper 110 between the carrying rollers 112 and 116. Therefore, when increased suction power is applied, the paper is apt to float up to a large extent, resulting in an unfixed image on the paper 110 possibly contacting to the upper surface of the transportation path (glass plate 103). This produces the fixed image on the paper 110 to adhere to a suction duct of the suction mechanism 104, causing a trouble in the print result such as dimmed print.
Furthermore, in order to increase the suction power, a large-scale suction blower (having large suction capability) is required. This brings about not only a larger blower in size but also increase of noise and cost. Another method for preventing the paper from fluttering during transportation is to suck the gas from the opposite side of the suction mechanism 104 across the paper 110. However, it is difficult to conduct air balancing, which makes it difficult to prevent from contacting to the paper 110. Moreover, the suction from the opposite side requires more suction capability than inherently required for the gas collection in the suction blower. This results in requiring a larger suction blower in size.
In a yet another method, it may be possible to increase the suction area while maintaining necessary suction time within a limit. This method also brings about larger suction mechanism 104 as well as larger suction blower, resulting in the unit substantially larger in size with increased noise and cost.
Accordingly, it is an object of the present invention to provide a flash fixation apparatus for improving efficiency in collecting gas (evaporated gas) produced from toner at the time of flash fixation while preventing a medium trouble in printing and a printer using the flash fixation apparatus.
It is another object of the present invention to provide a flash fixation apparatus for improving efficiency in collecting gas produced from toner at the time of flash fixation without applying large suction power in high-speed printing, and a printer using the flash fixation apparatus.
It is still another object of the present invention to provide a flash fixation apparatus for improving gas collection efficiency of the gas produced from toner at the time of flash fixation without need of a large unit in size even for high-speed printing, and a printer using the flash fixation apparatus.
Further, it is still another object of the present invention to provide a flash fixation apparatus for improving gas collection efficiency of the gas produced from toner during flash fixation while preventing a print medium under transportation from flattering, and a printer using the flash fixation apparatus.
To attain the above-mentioned objects, according to the present invention, a flash fixation apparatus for fixing a toner image on a medium under transportation by means of flash light includes; a flash fixation unit for emitting the flash light; a gas collector being disposed at the downstream side toward the medium transportation direction of the flash fixation unit for collecting vapor gas produced in flash fixation; and a guide being disposed between the flash fixation unit and the gas collector for altering the medium transportation direction. The aforementioned gas collector has a gas suction face disposed along the altered transportation direction.
Further, according to the present invention, a printer for forming a toner image onto a medium being transported at a predetermined transportation velocity includes; an image forming unit for forming a toner image onto the medium; and a flash fixation unit for fixing the toner image generated on the medium by means of flashlight. The flash fixation unit further includes, a flash fixation device for emitting the flash light; a gas collector being disposed at the downstream side toward the medium transportation direction of the flash fixation device for collecting vapor gas produced in flash fixation; and a guide being disposed between the flash fixation device and the gas collector for altering the medium transportation direction. Here, the gas collector has a gas suction face disposed along the altered transportation direction.
In the flash fixation apparatus of the present invention, vapor gas produced in flash fixation flows toward the medium transportation direction. Considering this, a guide for altering the medium transportation direction is provided at the entry of the gas collector. Further a gas suction face is provided so as to receive the vapor gas which flows along the altered medium transportation direction. Thus, the vapor gas flows into the gas suction face naturally, bringing about improved gas collection efficiency.
As a result, higher printing speed can be attained. In addition, it becomes possible, to collect vapor gas without increasing either suction power or suction area of the gas collector even when the vapor gas amount is increased, as well as to avoid medium flattering which may possibly occur at the time of medium transportation. Thus a miniaturized and low-cost flash fixation unit can be obtained.
According to the present invention, preferably the aforementioned gas suction face is directed to the vapor gas flow direction.
Further, according to the present invention, preferably a second guide for guiding the medium is provided on the exit (downstream) side of the gas collector. This enables to sustain medium tension at the gas collector so that medium flattering can be avoided even when high-speed printing is carried out, as well as enabling low-tension medium for use.
Still further, according to the present invention, preferably an angle of the gas suction face is maintained no more than 90 degrees against the medium transportation direction. This enables to guide the vapor gas flow effectively toward the gas suction face.
Further, the flash fixation apparatus in accordance with the present invention includes; a flash fixation unit for emitting the flash light; a gas suction unit being disposed at the downstream side toward the medium transportation direction of the flash fixation unit for sucking vapor gas produced in flash fixation; and a gas blast mechanism for blasting gas to the medium being disposed at the downstream side of the gas suction unit.
According to the present invention, the printer for forming a toner image onto a medium being transported at a predetermined transportation velocity includes an image forming unit for forming a toner image onto the medium; and a flash fixation unit for fixing the toner image generated on the medium by means of flashlight. The flash fixation unit further includes; a flash fixation device for emitting the flash light; a gas suction unit being disposed at the downstream side toward the medium transportation direction of the flash fixation device for sucking vapor gas produced in flash fixation; and a gas blast mechanism for blasting gas to the medium being disposed at the downstream side of the gas suction portion.
In this embodiment of the present invention, there are provided a gas collector for collecting vapor gas which flows in this transportation direction and a gas blast portion at the rear stage of the gas collector in the flash fixing device, considering that vapor gas produced in flash fixation flows toward the medium transportation direction. This constitutes an air curtain at the exit (downstream side) of the gas collector, preventing the vapor gas from leaking out of the gas collector and thus improving gas collection efficiency.
As a result, higher medium printing speed can be attained. In addition, it becomes possible to collect vapor gas without increasing either suction power or suction area of the gas collector even when the vapor gas amount is increased, as well as to prevent the medium under transportation from flattering. Thus a miniaturized and low-cost flash fixation unit can be obtained.
Also, according to the present invention, preferably the capacity of the gas blast mechanism is set larger than the capacity of the gas suction portion, which improves gas collection efficiency.
Further, according to the present invention, preferably a level difference is provided between the outlet of the blast mechanism and the intake of the gas suction portion, which improves gas collection efficiency.
Still further, according to the present invention, preferably there is further provided a circulation mechanism for filtering the suction gas being sucked in the gas suction portion to circulate to the blast mechanism. This reduces an exhaust gas to be output externally, which contributes to maintain the environment as well as obtains improved gas collection efficiency.
Further scopes and features of the present invention will become more apparent by the following description of the embodiments with the accompanied drawings.